Transducers that convert signals from one domain to another are often used in sensors. A common transducer used as a sensor is a pressure sensor that converts pressure differences and/or pressure changes to electrical signals. Pressure sensors have numerous applications including, for example, atmospheric pressure sensing, altitude sensing, and weather monitoring.
Microelectromechanical system (MEMS) based sensors include a family of transducers produced using micromachining techniques. MEMS, such as a MEMS pressure sensor, gather information from the environment by measuring the change of physical state in the transducer and transferring the signal to be processed by the electronics, which are connected to the MEMS sensor. MEMS devices may be manufactured using micromachining fabrication techniques similar to those used for integrated circuits.
MEMS devices may be designed to function as gas sensors, oscillators, resonators, accelerometers, gyroscopes, pressure sensors, microphones, and/or micro-mirrors, for example. Many MEMS devices use capacitive sensing techniques for transducing the physical phenomenon into electrical signals. In such applications, the capacitance change in the sensor is converted to a voltage or current signal using interface circuits. Other MEMS devices use resistive sensing techniques for transducing the physical phenomenon into electrical signals. In such applications, the resistive change in the sensor is converted to a voltage or current signal using interface circuits.
One type of example device is a gas sensor. Some gas sensors measure the resistance through a gas sensitive layer. For example, a humidity sensor may measure the resistance through a sensitive layer that absorbs water moisture from the air. As the water moisture is absorbed into the sensitive layer, the resistance of the layer is altered based on the humidity. Such humidity sensors may also include a heating element for use with the gas sensor.
For transducers that interact with an external environment, the device package may influence performance. For example, the device package may provide openings to the external environment and structural coupling or support to various sensing devices, such as a gas sensor, within the device package. The implementation of such structural supports or device packages provides opportunity for innovative implementations with expanded performance characteristics.